Tribal Connection: Trends in Stream Temperature in the Snake River

Weather and Climate
Stream Temperature
This feature tracks the summer water temperature of the Snake River.

This feature tracks the summer water temperature of the Snake River.

Figures

Figure 1. Average August Temperature in the Snake River, 1960–2022

Data source: U.S. Geological Survey, 2023
Web update: September 2023

Figure data (CSV) EPA source data (CSV)

Figure 1

This graph shows average August water temperatures at a site along the Snake River in eastern Washington.

Show the data behind this figure
Year August mean temperature (°F)
1960 70.83
1961 74.33
1962 71.93
1963 72.80
1964 69.64
1965 70.88
1966 71.25
1967 73.46
1968 69.60
1969 67.10
1970 71.89
1971 71.61
1972 73.89
1973 71.03
1974 68.61
1976 68.62
1977 70.64
1978 68.83
1979 71.63
1980 69.83
1981 72.05
1982 70.42
1983 71.80
1986 73.02
1987 70.74
1988 70.47
1989 71.37
1990 71.72
1991 71.95
1992 71.18
1993 69.35
1994 73.10
1995 70.53
1996 70.32
1997 72.24
1998 74.24
1999 71.69
2000 71.14
2001 72.18
2002 70.73
2003 72.96
2004 71.89
2005 71.87
2006 72.00
2007 71.63
2008 71.62
2009 72.06
2010 71.19
2011 71.71
2012 72.66
2013 72.95
2014 72.24
2015 72.63
2016 72.15
2017 73.08
2018 73.23
2019 73.39
2020 72.81
2021 72.83
2022 73.51
Figure 2

Background

Climate change has challenged and will continue to challenge some of the traditional ways of life that have sustained indigenous peoples for thousands of years. In the Pacific Northwest, warming river and stream temperatures will threaten ecosystems and species, including salmon populations.1 Salmon play a particularly important role in the diet, culture, religion, and economy of Native Americans in this region.2

Salmon are sensitive to water temperature at many stages of their lives. They spend much of their adult lives in the ocean, then migrate inland to spawn. Salmon need cold water to migrate and for their young to hatch and grow successfully. Warmer water can negatively affect fish, making it more difficult for them to swim upstream. It can also make fish more susceptible to disease.3 River and stream temperatures in the Pacific Northwest are influenced by many factors, but are expected to rise as average air temperatures increase (see the U.S. and Global Temperature indicator).4,5,6

The graph shows average August water temperatures at a site in the Snake River, in eastern Washington near Nez Perce tribal lands. Several species of salmon use the Snake River to migrate and spawn. Between 1960 and 2022, water temperature has increased by 2.2°F.

For this and other examples of community connections to observed climate-related changes, see EPA’s StoryMap.

Technical Documentation

References

  1. USGCRP (U.S. Global Change Research Program). 2018. Impacts, risks, and adaptation in the United States: Fourth National Climate Assessment, volume II. Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart, eds. https://nca2018.globalchange.gov. doi:10.7930/NCA4.2018.
  2. Dittmer, K. 2013. Changing streamflow on Columbia basin tribal lands—Climate change and salmon. Climatic Change 120(3):627–641.
  3. U.S. EPA (U.S. Environmental Protection Agency). 2001. Issue paper 5: Summary of technical literature examining the physiological effects of temperature on salmonids. EPA-910-D-01-005.
  4. Caissie, D. 2006. The thermal regime of rivers: A review. Freshwater Biol. 51:1389–1406.
  5. Van Vliet, M.T.H., F. Ludwig, and P. Kabat. 2013. Global streamflow and thermal habitats of freshwater fishes under climate change. Climatic Change 121:739–754.
  6. Isaak, D.J., S. Wollrab, D. Horan, and G. Chandler. 2012. Climate change effects on stream and river temperatures across the Northwest U.S. from 1980–2009 and implications for salmonid fishes. Climatic Change 113:499–524.
  7. USGS (U.S. Geological Survey). 2023. Analysis of data from the National Water Information System. Accessed February 2023.

Text on this page is EPA’s own published wording (a U.S. Government work, not subject to domestic copyright), extracted from EPA’s published indicator page by the build-indicator skill. Data, chart code, and the full extraction pipeline are maintained in the snake-river repository, which this page reads its data from directly.

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